Special Physics Seminar

Protoplanetary Disks and Planet Formation:
A Microphysical Perspective

Xuening Bai

Harvard-Smithsonian Center for Astrophysics

Planet formation takes place in gas-rich protoplanetary disks (PPDs) orbiting newly born stars. The internal density and flow structures of PPDs, as well as their long-term evolution, play a crucial role in almost all stages of planet formation, yet they are far from being well understood largely due to the complex interplay among various microphysical processes. Such lack of understanding also leads to major uncertainties in interpreting disk observations and exoplanet discoveries. I will review the basic physical processes in PPDs that govern disk structure and evolution, highlighting the fundamental role of disk ionization and magnetic fields. I will then describe my effort of incorporating and understanding these processes, both analytically and (primarily) computationally, towards building up the most realistic global evolutionary picture of PPDs. In particular, these efforts have led to a paradigm shift in understanding PPD gas dynamics, with major implications on planet formation. Finally, I will discuss future directions, in particular how the advanced computational tools will transform the science on PPDs and the formation of (exo-)planetary systems.